The present invention relates to a magnetic resonance imaging apparatus wherein a patient is disposed within an air-core of a static magnetic field generating means which forms a static magnetic field a gradient coil forms a gradient magnetic field within the air-core and a tomogram of the patient is imaged, and more particularly relates to the magnetic resonance imaging apparatus having a voice communication apparatus which is suitable for transmitting an operator's voice to the patient directly.
The conventional magnetic resonance imaging apparatus is constructed with a magnetic shielding room around the static magnetic field generating means which prevents the static magnetic field from being effected by electrically conductive materials at the outside of the magnetic shielding room so as to keep a homogeneity of the static magnetic field, and an electric wave shielding room around the magnetic shielding room for stably receiving an imaging signal generated by magnetic resonance phenomenon without receiving any affection of external noise.
In imaging the tomogram of the patient using the magnetic resonance imaging apparatus, it is necessary for the operator to communicate with the patient using a voice communication apparatus in order to correctly and speed by understand the state or the condition of the patient.
In the general magnetic resonance imaging apparatus, the most popular one is an apparatus having a voice tube using an electrically non-conductive material, wherein one side of the voice tube is close to the mouth of the patient and the other side is close to a microphone which transmits the patient's voice to the operator who is outside of the shielding room. On the other side, the operator's voice is transmitted to the patient by a loudspeaker which is installed on a wall or a ceiling in the shielding room.
The Japanese Patent Laid-open No. 60-207653 and the Japanese Utility Model Laid-open No. 61-16105 are cited as examples of such device.
But the conventional technique as stated above has the following drawbacks.
(1) As the voice tube is set close to the mouth of the patient, the patient could not help feeling a sense of oppression of the voice tube. It is troublesome for the patient.
(2) In imaging the tomogram of the patient, a striking sound is generated from the gradient coil and is transmitted with the patient's voice to the operator through the voice tube. It is difficult for the operator to distinguish the patient's voice from the striking sound. Furthermore, as the patient always moves in order to change the position of the patient's body which is being imaged, it is very difficult to set the voice tube at a position so as to be able to reduce the striking sound and thereby enable distinguishing of the patient's voice from the striking sound.